New Porous High Surface Area, TiO 2 Anatase/SAPO‐35 Mild Brønsted Acidic Nanocomposite: Synthesis, Characterization and Studies on it's Enhanced Photocatalytic Activity.

Anatase TiO 2 and Levyne type microporous silico alumino phosphate SAPO‐35 are synthesized by using hydrothermal method. TiO 2 /SAPO‐35 nanocomposites were prepared by sol‐gel method with different weight ratios. The synthesized materials were characterized by various analytical techniques such as PXRD, SEM/EDAX, TG/DTA, BET‐Surface area, FT‐IR, UV‐Vis, XPS, MAS‐NMR and photocatalytic study. From PXRD results it clearly evidenced that, the TiO 2 anatase peaks and SAPO‐35 combined peaks are in the composite. The spherical shaped TiO 2 nanoparticles were found to be dispersed over the rhombohedral SAPO‐35 particles, which was analysed by SEM. BET‐surface area analysis revealed that, the calcined SAPO‐35 has the surface area of 448 m 2 /g, was decreased to 222 m 2 /g for composite which is due to the presence of TiO 2 particles having surface area of 85 m 2 /g on the surface of SAPO‐35. The oxidation state and co‐ordination of various elements present in nanocomposite was composed by X‐ray photoelectron spectroscopy. MAS‐NMR analysis has shown that SAPO‐35 has tetrahedral Al, P and Si oxides. Eventhough Al is unique Si and P are in two different environment namely one in S6R and another in D6R with double intensity. The photocatalytic performance of methylene blue degradation under sunlight radiation by the synthesized TiO 2 /SAPO‐35 was analyzed. The TiO 2 /SAPO‐35 composites degrade the methylene blue under sunlight irradiation in 25 minutes against 90 minuts for pure TiO 2 anatase. A plausible mechanism on photocatalytic activity is also proposed.